1. Field of the Invention
The present invention relates to a liquid crystal display device having test architecture and related test method, and more particularly, to a liquid crystal display device having test architecture for performing an accurate defect detection operation and related test method.
2. Description of the Prior Art
Because liquid crystal display (LCD) devices are characterized by thin appearance, low power consumption, and low radiation, LCD devices have been widely applied in various electronic products for panel displaying. In general, the LCD device comprises liquid crystal cells encapsulated by two substrates and a backlight module for providing a light source. The operation of an LCD device is featured by varying voltage drops between opposite sides of the liquid crystal cells for twisting the angles of the liquid crystal molecules of the liquid crystal cells so that the transparency of the liquid crystal cells can be controlled for illustrating images with the aid of the backlight module.
Along with the demand of high display resolution on the LCD device, the elements integrated in the LCD device have been sized down for achieving high integrity, and therefore any tiny defect or particle contamination may degrade display quality significantly. That is, the production line for fabricating LCD devices having high display resolution is getting hard to achieve high yields. Accordingly, in the fabrication of the LCD devices, the defect detection operation is an important process for ensuring high product quality. Also, the defect detection operation can be utilized to get rid of the flawed semi-finished products in a real time for saving production cost. Furthermore, by making an analysis on the results of the defect detection operation, the cause of the defects can be analyzed for providing valuable information regarding systematic problems with the fabrication process, especially while bringing up a new fabrication process. In other words, the defect detection operation on semi-finished products can be applied to improve the health of the fabrication process.
It is well known that each pixel unit of an LCD device can be designed to include two sub-pixel units for achieving a wide viewing angle. That is, based on gray level averaging effect of two Gamma curves corresponding to the two sub-pixel units, optimal visual experience can be realized in different viewing angles for having a high-quality wide viewing angle. In general, the short-circuit defect of the LCD device occurs between adjacent sub-pixel units, and therefore the defect detection operation for detecting the short-circuit defect between adjacent sub-pixel units is critical to the process control of the production line for fabricating LCD devices. However, in the prior-art defect detection operation for detecting the short-circuit defects between adjacent sub-pixel units, only parts of the short-circuit defects can be detected. Consequently, not all the flawed semi-finished products can be thrown away in a real time for saving production cost, and the results of the prior-art defect detection operation cannot provide enough information for improving the health of the fabrication process so as to achieve high yields.